It was suggested we had too much moisture in house so we turned it off over a year ago and doesn't seem to have made a difference.

1. Get a hygrometer so you know the amount of humidity in your home. You may need a dehumidifier if your home remains over 50% humidity on a regular basis. A stand-alone (table top) humidifier filled with tap water will distribute a fine layer of white calcium mineral powder if you have hard water, so when using one use distilled water or reverse osmosis water to prevent the hard water scale. If your humidifier is connected to your furnace, does it need some kind of a filter to prevent hard water scale?

2. How often do you change the HVAC filter/s? You might try installing a new filter and leave your HVAC fan on "constant" for a week or two and see if more air-flow will help.

3. I'd pass the information on to your HVAC technician and have them check things when you have your unit serviced this spring. I would be concerned the substance is coming from your ducts and they may need cleaned, or replaced if this is some kind of mold (which it seems likely to me).

4. Make sure you vacuum your vents and air returns on a regular basis. It's a little thing that may be a contributing factor.

Hi Grainlady_ks, I appreciate the suggestions. We do have a hygrometer and it is below 50%, usually between 42-47%. We change the HVAC filters twice a year and the fan is on "constant" We also had a new return air put in by heating/ac company per their suggestion which didn't help either. We have not tried cleaning the ducts so I will certainly try that since we can't figure out what else to try and I didn't think of this. Thank you so much for your suggestions. I really do appreciate you taking the time.

How long have you lived in the house? And when did this start? Could it be a new finish on a surface that was not properly prepared and what's under the varnish or paint is coming through?

We built the house in 2001. We noticed after a year on a glass desk that was located by a window so we moved it out of the room. The wood furniture is scattered throughout the house and at first when I noticed spots, I thought it was our dog....but the dog is gone and about 2 months ago when I was getting a wall ready to paint, I noticed spots on the walls when the sun was hitting it just right. The furniture that I put the photo on we have had for about 4 years and was in my son's bedroom and it came out not more than 6 months ago.